A secondary battery which is high in application easiness according to a product group and has electrical characteristics including high energy density, and the like is universally applied to an electric vehicle (EV) driven by an electric driving source, a hybrid vehicle (HV) or an energy storage system (ESS) or an uninterruptible power supply (UPS) system using a medium/large battery used for a house or an industry as well as a portable device.
The secondary battery has received public attention as a new energy source for promoting eco-friendly performance and energy efficiency in that byproducts are not generated at all according to the use of the energy as well as a primary advantage of dramatically reducing the use of fossil fuels.
When the secondary battery is implemented as a battery of a portable terminal, or the like, it may not particularly be applied as above, but the battery applied to the electric vehicle or an energy storage source is used in a type in which a plurality of unit secondary battery cells is generally aggregated and used to increase suitability for a high-capacity environment.
When the plurality of unit secondary battery cells is aggregated and used, a problem may occur in which a unit cell is swollen and broken due to overheat, etc., in the case where an operation abnormality such as the flow of overcurrent, etc. occurs, and as a result, it should be considered that overcharging or overdischarging needs to be prevented from being applied to the unit cells by continuously measuring and monitoring various state values of voltages, temperatures, and the like of respective individual cells.
In the related art, the voltage and the current of a secondary battery module are measured and a shunt resistor for measuring current, which is connected to a busbar or a resistor connection unit is used while being connected to printed circuit boards (PCBs) 13 included in the secondary battery module and a secondary battery pack in order to determine overvoltage and overcurrent states through the measured voltage and current. In the related art, as illustrated in FIG. 1, a structure in which a banding type shunt resistor is mounted on the PCB 13 and a jig 14 is attached on the bottom of a resistor connection body 12 close to the shunt resistance 11 is used. In this case, since a resistance value of the shunt resistance 11 varies according to attachment locations of the jig 14 and the resistor connection body 12, the resistance value is not constant and an error occurs. As a result, it may be difficult to accurately diagnose a state of a battery based on current and voltage values measured from the shunt resistance 11.
Therefore, it is necessary to select an accurate location to be connected with a printing pattern of the PCB and reliability of the voltage and the current of the battery, which are measured from the shunt resistance 11 needs to be increased by preventing the resistance value of the shunt resistance 11 from being varied due to a component for connection with the PCB 13 through the selection of the accurate location.